Add image and internal-link reminders to template

blog/archetypes/default.md

@@ -9,3 +9,13 @@ tags:
 This is the introduction
 <!--more-->
 And this is the rest of the content
+
+<!--
+Reminders of patterns you often forget:
+
+Images:
+![Alt-text](url "Caption")
+
+Internal links:
+[Link-text]({{< ref "/posts/name-of-post" >}})
+-->